The present invention relates to optical scanners and more specifically to a counter rotating optical scanning unit.
Optical scanners are well known for their usefulness in retail checkout and inventory control. Optical scanners generally employ a laser, the light from which is focused and collimated to produce a scanning beam. A mirrored spinner directs the beam against a plurality of stationary mirrors, and a detector collects the beam after it is reflected by a bar code label. A motor rotates the spinner. The pattern produced by such a scanner is characterized by lines oriented at various angles to one another.
Industrial scanners require a truly omnidirectional pattern. Analysis of bar code label aspect ratios and sweep through speeds has shown that a symmetric pattern is optimum.
Industrial scanners must also be capable of scanning bar code information on items having a wide range in size.
Therefore, it would be desirable to provide an optical scanner which produces an omnidirectional pattern. It would also be desirable to provide a multiple depth of field optical scanner which is suited to the range of item sizes.